Core barrel assembly



4 Sheets-Sheet 1 J. H. KOONTZ ETAL CORE BARREL ASSEMBLY JAMES H. KOONTZ ROBERT A MILLER ATTORNEY Dec. 28, 1965 Filed Feb. 17, 1961 Dec. 28, 1965 H. KQONTZ ETAL 3,225,845

CORE BARREL ASSEMBLY WWW ATTORNEY 1965 J. H. KOONTZ ETAL 3,225,345

CORE BARREL ASSEMBLY 4 Sheets-Sheet 4 Filed Feb. 17,1961

FIG. 8

FIG. IO

lNVENTORS JAMES H KOONTZ BY ROBERT AAMILLER ATTORNEY United States Patent Ofiice 3,225,845 Patented Dec. 28, 1965 3,225,845 CORE BARREL ASSEMBLY James H. Koontz, Michigan (Iity, and Robert A. Miller, Culver, Ind., assignors to Joy Manufacturing Company, Pittsburgh, Pa., a corporation of Pennsylvania Filed Feb. 17, 1961, Ser. No. 89,994 3 Claims. (Cl. 175-236) This invention relates to an improved drilling apparatus and more particularly to an improved wire line core barrel assembly and overshot whereby an elongated hole may be rapidly drilled.

As is well known the purpose of core drilling is to obtain as great a length of core as is possible in the form in which it exists in the underground formation through which the drill bit has passed. The various core lengths are then removed and stored for inspection purposes. In such drilling art a series of long drill rods or tubes is coupled together in longitudinal relationship and has an elongated tube at its drilling end which carries the drilling bit. Such a series of tubes is commonly called a drill string which carries at its lower end a core barrel assembly. Although various methods of drilling are known, one preferred method of drilling is by means of a wire line core barrel. This method utilizes a detachable inner tube and head assembly which can be quickly and easily removed by an overshot device without the removal of the drill string per se. Heretofore wire line barrels have had many disadvantages whereby they cannot be universally employed. Prior wire line core barrels have in general been of a rather intricate structure having water shut Oif means easily subject to failure. In addition the removal of the inner tube and head assembly from the drilled bore hole was time consuming. The present invention provides a reliable balanced drilling fluid shut-off valve that is extremely effective, which is cooperative with a novel overshot assembly wherein the overshot assembly facilitates easy removal of the core sample and assures maximum safety for the interrelated inner tube and head assembly so that there is no release of the parts until the inner tube and head assembly is properly seated and connected to the drill string.

Accordingly, an object of this invention is to provide a drilling apparatus having a new and improved wire line core barrel.

A further object of this invention is to provide a drilling apparatus having a new and improved overshot device cooperative with the inner tube and head assembly of the wire line core barrel to facilitate handling thereof.

. A further object of this invention is to provide a new and improved wire line drilling apparatus having a pivotally hinged overshot assembly with a pivotally connected core receiver tube which facilitates the handling of a core barrel unit for easy removal of the core sample.

A further object of this invention is to provide a drilling apparatus having a new and improved water shut off valve for a wire line core barrel.

A further object of this invention is to provide a new and improved wire line core barrel having a pressure balanced shut-off valve cooperative with the inner tube assembly which shuts off the water flow completely upon blockage or filling up of the core receiver tube.

A further object of this invention is to provide a new and improved wire line drilling apparatus having an overshot assembly which assures complete connection between the inner tube and head assembly with the drill string before it releases from the head assembly.

These and other objects and advantages of the invention will hereinafter more fully appear. In the accompanying drawings there are shown for purposes of illustration one form and modifications which the invention may assume in practice.

In these drawings:

FIGURES 1, 2 and 3 are longitudinal cross sectional views, having portions thereof shown in elevation, of a drilling apparatus constructed in accordance with the principles of this invention which when longitudinally aligned with a gap between FIGS. 1 and 2 and some overlapping of FIGS. 2 and 3 show the entire drilling apparatus of this invention.

FIGURE 4 is a longitudinal cross sectional view, having portions thereof shown in elevation of the drilling apparatus shown in FIGURE 2 showing the overshot assembly with an overshot release coupled thereon when lowering the inner tube and head assembly into a drilled hole constructed in accordance with the principles of this invention.

FIGURE 5 is a perspective elevational view of the sleeve member of the overshot assembly.

FIGURE 6 is an enlarged cross sectional elevational view of the sleeve member of the overshot assembly.

FIGURE 7 is an enlarged cross sectional elevational view of a portion of the valve and tubular sleeve memher in cooperative relationship with the lower portion of the coupling section shown in FIGURE 3 wherein a line A'A' at the bottom of FIG. 7 indicates the same level on the drilling apparatus as that indicated by a line A-A at the top of FIG. 3.

FIGURE 8 is an enlarged cross sectional elevational view of a portion of the head assembly showing the overshot release coupled thereto in accordance with the principles of this invention.

FIGURE 9 is an enlarged cross sectional elevational view of a portion of the head assembly showing the overshot release uncoupled therefrom.

FIGURE 10 is an enlarged elevational view of a portion of the head assembly showing the upper portion of the spearhead.

Referring to FIGURES 1, 2 and 3 a plurality of elongated tube sections or drill rods 1, only some of which are shown, are suitably connected together in axial alignment in a manner as is well known in the art such as by threads '7 to form an elongated tubular drill string. An elongated tubular coupling section 2 (FIG. 2) is threadedly secured between the lowermost drill rod 1 of the drill string and an elongated outer tubular member 200 which tubular member 20% is concentric with drill rod 1 and of substantially the same wall thickness as drill rods 1 except that tubular member 200 is shorter in length than drill rods 1. The coupling section 2 has an intermediate longitudinally elongated annular groove 86 extending radially outwardly of the inner surface thereof, which groove 86 is larger in diameter than the inner diameters of the drill rods 1. At the lower end portion of coupling section 2 an annular shoulder 87 projects radially inwardly from the inner wall surface thereof. The bore as defined by the annular shoulder 87 is smaller in diameter than the inner diameter of the drill rod as well as smaller in diameter than the diameter of the groove 86. A tubular drill bit 4 (FIG. 3) is secured at its upper end such as by threads 5 to the lower end of a reamer shell 6, which reamer shell 6 is connected in any suitable manner such as by thread 5' to the lower end of the outer tubular member 200. Bit 4 may be of any suitable type of construction as is well known in the art. Suitable cutting means such as diamonds 10 are suitably supported on the bottom surface and the outside and inside surfaces adjacent to the bottom surface of tubular drill bit 4. The lowermost end portion of tubular bit 4 is laterally inwardly enlarged forming a bore through which the cut core passes upon relative downward movement of the drill string during the drilling operation as is well understood in the art. The top inner annular surface of the inwardly enlarged lower end portion of tubular bit 4 is upwardly and outwardly tapering to provide an alignment shoulder 8 for a purpose to be described.

As shown in FIGURE 3 an elongated tubular core receiver tube or inner tube 20 is suitably positioned in the lowermost end of the drill string. The upper end of a tubular core lifter case 16 of any well known construction is suitably secured to the lowermost end of inner tube 20. The core lifter case 16 is aligned substantially by the top annular surface or alignment shoulder 8 of the bit 4. The core lifter case 16 has a movable core lifter 17 suitably slidably located therein for gripping, breaking and holding a drilled core when the drill string is backed off as is well known and understood in the art.

With the structure heretofore described rotation of the drill string causes bit 4 to rotate, wherein the diamonds cut a core having an external diameter approximately equal to the distance between the outer cutting edges of the diamonds 10 on the inner surface of the tubular bit 4. In such drilling, the drilled core passes through the opening into the lower portion of the tubular bit 4 and into and through the core lifter 17 into the inner tube or core receiver tube 20. The cut core gradually rises upwardly through the length of the inner tube 20 as the drill string passes downwardly until the length of the inner tube 20 thereof is full of cut core or blocked due to breakage of the core. Accordingly, the core receiver 26 is filled or blocked as is well understood in the art, the drill string is slightly elevated so that the core lifter case 16 is also elevated relative to the core lifter 17 and to the core which is firmly attached to the ground formation. Such elevation causes the core lifter 17 to be reduced in its cross section due to the wedging action of the tapering sides of the core lifter case 16 relative thereto, and as the elevation continues the cut core is broken from the ground formation and is locked by the core lifter 17 to the inner tube 24 whereby a cut core portion not shown is provided within the inner tube 20. The inner tube 20 with the core lifter case 16 attached thereto forms the lower portion of an elongated specially constructed inner tube and head assembly, the upper end of which has an elongated spearhead 28 extending upwardly and tapering to a point 31 within the drill string.

In order to remove the inner tube and head assembly from the drill string an elongated latch assembly which is generally known as an overshot (FIG. 1) and is so identified hereinafter is lowered by means of a wire cable 13 into engagement with a spearhead 28 of the inner tube and head assembly. The head assembly consists of a plurality of shafts, collars, sleeves and an annular head that are suitably connected for a purpose as is more clearly evident from the accompanying description. The upper end of the cylindrical stepped spearhead 28 (FIGS. 2, 4 and 7) has a short cylindrical upper portion 29 with a forward tapering point 31 for a purpose to be described. Spaced downwardly from the cylindrical upper portion 29 is a cylindrical projection 32 larger in diameter than the upper cylindrical portion 29, which cylindrical projection 32 has adjacent converging annular surfaces defining an upper upwardly and inwardly inclined annular shoulder surface 33 which merges with the upper cylindrical portion 29 and a lower downwardly and inwardly inclined annular shoulder surface 34. The directions downwardly, upwardly, forwardly and rearwardly are used with respect to the figures disclosed for convenience and ease of understanding, and not intended to limit the scope of the invention. Extending downwardly from the lower inclined shoulder surface 34 is a cylindrical portion 37 (FIG. 9) smaller in diameter than the cylindrical projection 32. Extending downwardly and annularly outwardly from the cylindrical portion 37 substantially coextensive in limits and complementary to inclined surface 34 is an inclined annular surface 36 which together with inclined annular surface 34 defines a circular groove 35 therebetween on spearhead 28 for a purpose to be described hereinafter. Extending downwardly from the lower edge of downwardly and outwardly inclined annular surface 36 is an elongated cylindrical portion 39 of substantially the same diameter as the cylindrical projection 32, Extending downwardly from the cylindrical portion 39, spearhead 28 has an elongated cylindrical intermediate portion 40 (FIG. 2) of reduced diameter. Immemiately below and extending downwardly from the intermediate portion 40 is a cylindrical portion 41 of greater diameter than intermediate portion 40, below which is a longitudinally extending reduced diameter portion 42 terminating into a further reduced diameter longitudinal end portion 43 of shorter length than the cylindrical portion 42.

A tubular collar 60, closely slidably mounted on the intermediate portion 40 of the stepped cylindrical spearhead 28, has its lower end portion threadedly secured to the upper end portion of a tubular lock sleeve 61 which lock sleeve 61 has a plurality of laterally extending bores which extend radially through the intermediate portion thereof. The axes of the respective bores 65 lie in a plane that is normal to the longitudinal axis of the tubular sleeve 61. The upper portion of lock sleeve 61 is of a thin walled dimension whereas the lower portion of lock seleve 61 is of thick walled dimension, thereby presenting an upper portion with a bore 61 larger in diameter than the diameter of the lower bore 61" of the lower thick walled portion since the outer dimension of lock sleeve 61 is substantially uniform for all purposes. A plurality of balls 64 are suitably retained in rolling contact in the respective bores 65 for a limited lateral play therein as by deforming the outer side surfaces of sleeve 61 immediately adjacent the outer edge of each bore 65 to provide a reduced opening to bore 65 to thereby limit the outward movement and projection of the balls 64 from bores 65. The deformation of the side surfaces of sleeve 61 is similar to a staking operation however only sleeve 61 is deformed. The inward movement of balls 64 in the respective bores 65 may be limited by a fianging operation, peening, or some other auxiliary means. The lateral outward as well as the inward movement of balls 64 in the respective bores 65 are limited; however, a portion of balls 64 are adapted to project outwardly from their respective bores 65 a short distance to cooperate with annular groove 86 of coupling section 2 to connect the sleeve 61 of the head assembly to the drill string in a manner be described hereinafter. The lower longitudinally extending reduced diameter portion 42 of spearhead 28 is slidably received by bore 61 of the thick walled portion of tubular lock sleeve 61 for guided reciprocable movement to rollingly urge the balls 64 in the respective bores 65 outwardly into the annular groove 86 of coupling member 2. The upper annular surface of the thick-walled portion of tubular lock sleeve 61 provides a top annular shoulder surface 62 which abuttingly contacts a bottom annular surface 63 of the enlarged diameter portion 41 of the stepped spearhead 28. Enlarged diameter portion 41 is immediately above the reduced diameter portion 42 of stepped spearhead 28. A closed end spiral spring 66 is slidably mounted on the intermediate portion 40 of the stepped cylindrical spearhead 28, having the upper end of spring 66 in abutting contact with the lower bottom annular surface of collar 60, and having the lower end of spring 66 in abutting contact with the top annular surface of enlarged portion 41 of stepped spearhead 28 to thereby bias the enlarged portion 41 downward relative to tubular lock sleeve 61 which thereby causes the reduced diameter end portion 42 to be biased downward so that the outer wall surface of the reduced diameter portion 42 comes into rolling contact with the balls 64 to thereby force the balls 64 radially outwardly into locking engagement with the annular groove 86 of coupling section 2 of the drill string 1 to thereby secure the head assembly (including spearhead 28, tubular collar 60 and sleeve 61) to the coupling section 2 and the drill rods 1. As shown in FIGURE 4, whenever a force is exerted on the stepped spearhead 28 which causes a relative upward movement of the stepped spearhead 28 relative to the tubular collar 60 and the lock sleeve 61, the balls 64 will be free to come in rolling contact with the reduced end portion 43 of the stepped spearhead 28, which thereby permits the balls 64 to be free to recede from the annular groove 86 and correspondingly unlock and free the head assembly (including spearhead 28, collar 60 and lock sleeve 61) from the drill string to thereby permit the head assembly (sleeve 61, collar 60 and spearhead 28) to be moved upward relative to the drill string upon a further application of upward force to the stepped spearhead 28. The lower end of lock sleeve 61 is suitably connected by threads 69 to an upper end of a tubular stepped sleeve member 70 (FIG. 2). An outer annular shoulder 75 projects radially outward from the intermediate portion of sleeve member 70 for cooperative abutting contact with the annular shoulder 87 on the coupling member 2 of the drill string to limit the downward movement of the head assembly (sleeve 61, collar 60, spearhead 28, member 70) relative to the drill string. Spaced longitudinally upwardly from annular shoulder 75, sleeve member 70 has a plurality of radially extending bores 72 which direct fluid from the clearance space provided by the inner wall of the drill string (drill rods 1) and the outer wall of tubular sleeve member 78 radially inwardly into the inner portion of tubular mem ber 70. Spaced longitudinally downwardly from annular shoulder 75, sleeve member 70 has a plurality of radially extending bores 74 which direct fluid from the bore of sleeve member 70 radially outward into the clearance space provided by the outer wall surface of sleeve member 70 and the inner wall of the drill string (rods 1, coupling section 2). An annular seal 78 is located on the intermediate portion on the external surface of sleeve member 70 intermediately of the annular shoulder 75 and the radially extending bores 74 for sliding contact with the inside wall of coupling member 2 to prevent the passage of fluid thereabout as is well understood in the art. The seal 78 prevents the flow of fluid past the external surface of the sleeve member 70 and directs the fluid through the respective bores 72 and 74 from their respective clearance spaces as set forth above. A valve 90 (shown as a differently constructed valve 90' in FIG. 4), slidably located in the bore of tubular sleeve member 70, cooperates with the bores 72 and 74 in a manner as will be more fully explained hereinafter. Valve 90 has an upper enlarged cylindrical portion 91 slidably contacting the inner wall of the bore of tubular sleeve member 70 immediately above the bores 72 and an elongated intermediate reduced cylindrical portion 92 providing a clearance space 92 between the outer wall surface thereof and the inner wall surface of sleeve member 70 thereby communicating in its normal position the bores 72 and 74 through the clearance space 92 thereby provided (see FIG. 7). The bottom annular surface of the upper enlarged cylindrical portion 91 provides an annular shoulder 91' connecting the portion 91 to the reduced intermediate portion 92. Valve 90 has a lower enlarged cylindrical portion 93 slidably received by the inner wall surface of tubular member 70 closely adjacent the bores 74. The top annular surface of the lower enlarged cylindrical portion 93 (FIGS. 2 and 7) provides an annular shoulder 94 adjacent the lower end of the reduced intermediate cylindrical portion 92 of valve 90, which annular shoulder 94 tapers upwardly and inwardly from the enlarged portion 93 to the reduced portion 92 to cooperate with an annular shoulder 95 located on the inner wall surface of sleeve member 70 (FIGS. 2 and 7) which shoulder 95 is immediately above and adjacent to bores 74. Upon upward movement of valve 90 relative to sleeve member 70, annular shoulder 94 located on valve 90 abuttingly contacts annular shoulder 95 on the inner wall surface of sleeve member 76 and thereby seals off the flow of fluid to bores 74 from the bores 72 as is well understood in the art. When contacting annular shoulder 95 (see FIG. 2) the annular shoulder 94 has a portion thereof exposed to pressure fluid in the clearance space 92 which is substantially equal in area to the annular shoulder 91' at the upper end of portion 92 to achieve a balance between fluid forces tending to open valve 90 and those tending to hold it closed. Suitable annular seals are located on the respective upper and lower enlarged cylindrical portions 91 and 93 of valve 90 to prevent the leakage of fluids to thereby assure the proper functioning of valve 90.

The valve 90 of FIG. 4 has the same profile and the same functions as valve 90 of FIG. 2 but as shown in FIG. 4 valve 98' is produced by assembling a plurality of elements rather than by forming a single piece of material.

The lower end of tubular sleeve member 70 is suitably threadedly connected to an elongated tubular thrust collar 88 (FIG. 3) having a centrally longitudinally extending stepped bore 44, which thrust collar provides a relative sliding connection between the outer wall of an extension to be described of inner tube 20 and the inner wall of bore 44 of tubular sleeve member 70 as will become more apparent from the description to follow. Bore 44 of tubular collar 80 has an enlarged bore portion at the upper end thereof to provide an intermediately located inner annular shoulder surface 82 at the bottom of the enlarged bore portion thereof.

A stepped shaft 84 (FIG. 3) having an upper cylindrical enlarged diameter portion and an intermediate cylindrical portion 21 of reduced diameter has an annular abutment surface 22 on the bottom surface of the enlarged diameter cylindrical portion 85 which abuttingly contacts the top surface of a thrust bearing 86, mounted on the intermediate portion 21 of shaft 84, wherein the bottom annular surface 88 of thrust bearing 86 abuttingly contacts the annular shoulder 82 on collar 80. The uppermost top surface of shaft 84 abuttingly contacts the bottom end surface of a thrust bearing 96 whose top annular surface abuttingly engages the bottom surface of an annular spacer member 97 (FIGS. 3 and 2). The upper annular surface of spacer member 97 abuttingly engages the bottom annular surface of a lowermost spacer washer 98 of a group of spacer washers seated thereon in vertical stacked relationship as clearly shown in FIGS. 2 and 7. Spacer washers 98, spacer member 97 and thrust bearing 96 are mounted in sleeve member 70 with the outer surfaces of spacer washers 98 in sliding contact with the inner wall of sleeve member 70. The top surface of the uppermost spacer washer 98 abuttingly contacts the bottom surface of valve at the extreme lowermost position of valve 90 relative to sleeve 70 (see FIGS. 3 and 7), valve 90 abuts spacer washers 98, which spacer washers 98 abut spacer member 97, which in turn abuts thrust bearing96, which in turn abuts the top surface of stepped shaft 84, which has annular abutment surface 22 abuttingly engaging thrust bearing 86 which abuts annular shoulder 82 of collar 80 which is threadedly secured to sleeve 78 with the shoulder 75 of sleeve 70 being seated on the annular shoulder 87 (FIGS. 2 and 7) of coupling member 2.

Located in the upper bore portion of tubular sleeve member 70 is a plurality of Belleville type springs 181 of well known design having the lowermost surface in abutting contact with the top surface of valve 90 and having the uppermost surface in abutting contact with spacer washers 102 which uppermost washer 102 abuttingly contacts the bottom surface of tubular sleeve 61 previously described. The Belleville type springs 101 bias the spool valve 90 downwardly to maintain the bottom surface of valve 90 in abutting contact with the top surface of spacer washers 98 and thereby maintain communication between the upper bores 72 with the lower bores 74 of sleeve member 70 when the inner tube 28 is in the lower position relative to tubular member 280 as shown in FIG. 3.

The lower portion of intermediate portion 21 of shaft 84 (FIG. 3) is circumferentially recessed as at 23 for a purpose to be described. The lowermost end of shaft 84 is threadedly secured as by threads 24 to a lower portion of an annular head 83 which encompasses the major portion of shaft 84. The lower outer end of annular head 83 is suitably threaded to the top end portion of inner tube to thereby connect the inner tube 28 to the shaft 84 which upon upward movement such as when inner tube 20 is filled with a cut core is operative to move valve 98 upward relative to tubular sleeve member '78 into the position shown in FIG. 2 to shut off the flow of fluid through bores 74 and thereby signal the operator that the inner tube 20 is filled due to the rise in fluid pressure as is well understood in the art. The upper portion of annular head 83 being of reduced diameter is slidably received by an annular bearing member 38 which in turn is suitably secured to the lower inner diameter wall portion of collar 80' such as by press fitting. The intermediate portion of annular head 83 has a pair of diametrically opposed radially extending threaded bores and 26. Bore 25 has a pair of set screws 45 suitably threaded therein wherein the bottom edge surface of the innermost set screw 45 abuttingly engages a portion of the bottom surface of circumferential recess 23 to further secure shaft 84 to annular head 83 and inner tube 20. The intermediate portion of annular head 83 has a counterbore 27 extending from the outer surface thereof inwardly toward the central bore of the annular head 83 wherein counterbore 27 is coaxial with threaded bore 26 and communicates therewith, with the axes of bore 26 and 27 being normal to the longitudinal central axis of annular head 83. Suitably threadedly secured within threaded bore 26 is a grease fitting 46 to provide means for suitably lubricating the clearance space between the intermediate portion 21 of shaft 84 between thrust bearing 86 and the top annular surface of annular head 83 as Well as the outer surface of annular head 83 and the inner surface of annular bearing member 38.

The overshot assembly comprises a tubular jar member 120 having a centrally located longitudinally extending bore 123 with a coupling element 111 suitably threadedly connected to the upper end thereof and an annular jar head member 121 suitably threadedly connected to the lower end thereof as is well known in the art. A bore 122 in jar head member 121, smaller in diameter than bore 123 of the tubular jar member 120, has its inner surface in sliding contact with the outer wall surface of an elongated cylindrical shaft 127 suitably positioned therein. The uppermost end of shaft 127 has an annular plug member 128 suitably secured thereto with a bottom annular surface 126 of plug member 128 abuttingly contacting the top annular surface 125 of annular jar head member 121, thereby limiting the relative downward movement of shaft 127 with respect to annular jar head member 121 as is Well understood in the art.

An elongated sleeve member 130 (FIGS. 1, 5 and 6) having a pair of diametrically opposed longitudinal extending slots 134 in the upper portion thereof also has a pair of diametrically opposed slots 133 which extend from the upper top surface of sleeve member 130 downwardly therefrom bifurcating sleeve member 138 into two upper leg portions. Diametrically opposed slots 134 and diametrically opposed slots 133 lie in planes which are normal to each other with the intersection of the respective planes defining a line which is concentric with the longitudinal axis of sleeve member 130. The lowermost end of shaft 127 is suitably pivotally and slidably connected to sleeve member 130 by a transverse hinge pin 132 which extends through the lower end portion of shaft 127 with the respective end portions 132 of hinge pin 132 projecting later-ally outwardly into the respective slots 134 of sleeve member 1341 thereby guiding sleeve member 138 for limited reciprocal movement relative thereto. Mounted closely above hinge pin 132 on shaft 127 is a laterally extending pin 135 extending through shaft 127 with the respective ends thereof projecting into the respective slots 133 and slidingly contacting the sides of the slots 133 for guiding shaft 127 and sleeve member 130 in their relative reciprocal movement and preventing the twisting of member 138 relative to shaft 127. The longitudinal central bore of sleeve member 138 is of such length that the bottom end of the bore provides an annular seat for the lower end of shaft 127 before hinge pin 132 contacts the bottom of slot 134 so that in any jarring operation the shaft 127 is rigid with the sleeve member 130 and will not hinge relative thereto. A tubular member 140 is threadedly connected at its upper end to the lower end of sleeve member 138. Since tubular member 148 is smaller in diameter than sleeve member 130, the juncture thereby provides an annular shoulder 141 on the lower end surface of sleeve member 138 for a purpose to be described. A coupling sleeve member 145 (FIG. 2) is suitably threadedly connected to the lower end of tubular member 140 and since coupling sleeve member 145 is larger in diameter than tubular member 140 sleeve member 145 has a top annular shoulder surface 146 which abuttingly contacts the bottom annular surface of a spacer washer 149 which in turn has its upper annular surface abuttingly contacting the bottom annular surface of a spacer bushing member 148 which slidably encompasses the tubular member 148. The top annular surface of bushing member 148 abuttingly contacts the bottom annular surface of a washer 149' which in turn has its top annular surface abuttingly contacting the bottom annular surface 141 of sleeve member 130.

Elongated tubular coupling member 145 (FIGS. 2 and 8) has a longitudinal extending central bore 139 and a stepped outer cylindrical surface with an upper portion 146 and a lower portion 147 which lower portion 147 is Slightly larger in diameter than the upper portion 146. Coupling member 145 has a plurality of radially extending bores 180 (FIGS. 8 and 9) which extend from the outer surface of lower end of upper portion 146 inwardly and downwardly at an acute angle to the axis of central bore 139. The axis of the respective bores 180 make an acute angle with the longitudinal axis of upper portion 146 of tubular coupling member 145. The inner cylindrical surface of bore 139 of coupling member 145 immediately above the bores 180 has an upwardly and inwardly extending annular shoulder 182, and extending upward therefrom bore 139 is of reduced cross section to slidingly receive the forward portion 29 of the spearhead 28 to provide a sliding fit therebetweeu. The upper diverging shoulder 33 of spearhead 28 abuttingly contacts the annular shoulder 182 on coupling member 145 to limit the upward extent to which spearhead 28 enters the tubular coupling member 145. The lower bottom end face 183 of coupling members 145 lower portion 147 is annularly recessed as at 184 to provide a seat at the upper annular surface thereof for a closed end helical spring 151 to be further defined. A tubular formed cam sleeve 153 slidably encompasses coupling member 145 wherein cam sleeve 153 has an intermediate portion slidably mounted on the intermediately located cylindrical portion 39 of spearhead 28. The upper portion of the intermediate portion of coupling member 145 has an annular recess 154 extending downwardly therein, which recess 154 slidably receives the lower enlarged diameter portion 147 of coupling member 145. The bottom surface 155 of recess 154 has an annular recess 157 which is oppositely disposed and facing recess 184 of coupling member 145 so that recess 157 receives the bottom end of closed end helical spring 151 which biases cam sleeve 153 downwardly relative to coupling member 145. Slidably mounted in each downward inclined bore is a cylindrical locking pin 164 having its upper surface in abutting contact with an upper annular shoulder 163 on the inner diameter surface of the upper portion of cam sleeve 153' and having its lower surface in abutting contact with a lower annular shoulder 162 on the inner top surface of the intermediate portion of cam sleeve 153 (FIG. 8). Thus as cam sleeve 153 moves upward relative to coupling member 145, the lower annular shoulder 162 cams cylindrical locking pins 164 upward while simultaneously upper annular shoulder 163 moves upward. On downward movement of cam sleeve 153 relative to coupling member 145, upper annular shoulder 163 cams cylindrical locking pins 164 downwardly. In the normal position helical spring 151 biases cam sleeve 153 downward, simultaneously upper annular shoulder 163 cams cylindrical locking pins 164 downwardly with the lower end portions thereof projecting into annular groove 35 on spearhead 28 with the lower end portions of the locking pins 164 thereof being in abutting contact with the downwardly and inwardly inclined surface 34 of groove 35. Pins 164 thereby prevent the removal of spearhead 28 and lock the spearhead in position. By reeling in the wire line 13, the overshot assembly 30 is moved upwardly relative to the drill string (drill rods 1 and drill bit 4) from the drill hole raising simultaneously therewith the coupling member 145, the spearhead 28 and the inner tube 20 and head assembly (sleeeve 61, collar 60, member 70). Upon removal of the above units from the drill hole theinner tube 20 and head assembly is removed from the spearhead 28 by exerting an upward force on the cam sleeve member 153 while maintaining the spearhead 28 stationary which action by cam sleeve member 153 compresses spring 151 while the lower annular shoulder 162 of cam sleeve 153 cams locking pins 164 upwardly in the respective bores 180 into the clearance space created by the relativeupward movement of upper annular shoulder 163 (FIG. 6) so that spearhead 28 is free to move downward for removal from the central bore of the coupling member 145 as well as from the cam sleeve member 153 as is well understood in the art. In order to facilitate the removal of the cut core from the inner tube 20 when the head assembly and inner tube 20 are out of the drilled hole, the hinged pivotal connection between sleeve member 1307 and the shaft 127, namely hinged pin 132 permits the pivoting or swinging of the sleeve member 130 relative to shaft 127thereabout so that the end of shaft 127 clears sleeve member 130 through movement through slot 133 as hinge pin 132 contacts the upper end surface of slot 134 guiding the pivotal movement of sleeve member 130 relative to shaft 127. Thus as the overshot assembly (coupling element 111, jar member 120, jar head member 121, shaft 127) is depending from the derrick of the drilling apparatus via cable 13, sleeve member 130 is pivoted relative to shaft 127 as above described thereby extending sleeve member 130, along with the head assembly (including spearhead 28, tubular collar 60, sleeve 61, member 70) and the inner tube assembly 20 along the ground surface for convenient access to the removal of the core sample from the inner tube 20 as well as inspection of parts and easy access to removal of the head assembly from the spearhead 28.

To lower the core barrel into a bore hole a tubular overshot release coupling 170 (FIGS. 4, 8 and 9) having a bottom annular abutment surface 171 at the lower end thereof is suitably connected such as by a threaded connection to the lower portion of the cam sleeve 153 which thereby extends the longitudinal dimension of the overshot assembly particularly the longitudinal dimension below the coupling member 145, when coupling member 145 is connected or latched to the spearhead 28. Thus the bottom annular abutment surface 171 of release coupling 170 is closely adjacent the top annular surface of tubular collar 60 (FIGS. 4 and 8). Prior to inserting the overshot assembly and inner tube 20 into the drilled hole, spearhead 28 is suitably latched to the overshot assembly 30 by forcing the point 31 of spearhead 28 upwardly into cam sleeve member 153 until the upper diverging shoulder surface 33 abuttingly engages the locking pins 164 and earns them upwardly and outwardly until the annular projection 32 moves upwardly past the lower ends of locking pins 164 which thereafter are cammed into the annular groove 35 on downward biased movement of cam sleeve member 153 as when the annular shoulder 163 thereon engages the upper end of locking pins 164 and thereby urges them downwardly in the respective bores 180 into annular groove 35 for latching the overshot assembly 30 to the spearhead 28. The lower downwardly inclined shoulder surface 34 abuttingly engages the cylindrical pins 164 and thereby secures the spearhead to the coupling member 145 and the sleeve member of the overshot assembly 30. The overshot assembly 30 thus properly secured to the spearhead 28 and the inner tube 20 is then lowered into the bore hole and the drill string until the inner tube 20 is seated at the bottom of the drilled hole, wherein the release of the overshot 30 from the inner tube 20 and head assembly is accomplished when annular shoulder 75 on the sleeve member 70 of the head assembly abuttingly engages the stationary annular shoulder 87 on the coupling member 2 of the drill string to thereby limit further downward movement of the sleeve 70; the momentum of the overshot assembly 30 and the spearhead 28 which is spring loaded continues to descend downwardly into the drill string thereby moving spearhead 28 as well as its enlarged portion 42 downwardly which enlarged portion 42 cams the locking balls 64 radially outwardly into rolling locking contact with the annular groove 86 in coupling section 2 to thereby lock the inner tube 20 and head assembly to the drill string. The spearhead 28 and the overshot 30 continue to descend due to their momentum until the overshot release coupling 170 which is the lowermost element of the overshot assembly abuttingly engages the top annular surface of the tubular collar 60 to thereby stop the downward movement of the cam sleeve member 153 as well as downward movement of overshot release coupling 170, however coupling member and spearhead 28 continue downwardly due to their momentum as well as the momentum of the upper elements of the overshot assembly to thereby compress spiral spring 151 (FIG. 9), to provide relative movement between coupling member 145 and cam sleeve 153 which movement causes cam sleeve 153 to cam the locking pins 164 upwardly, out of annular groove 35 and thereby releases the abutting engagement of locking pins 164 with the annular shoulder projection 32 on spearhead 28. The spring 66 biases spearhead 28 further downward until shoulder 63 abuttingly engages shoulder 62. This last movement of spearhead 28 by spring 66 moves spearhead 28 beyond the position for reattachment by overshot assembly 38 to thereby permit the upward withdrawal of the overshot assembly (jar member 120, coupling element 111, sleeve 130, coupling member 145, cam sleeve 153 and release coupling upon external upward force exerted thereon. The drill string is thus in position to drill while the inner tube 20 is in position to receive a cut core. The overshot assembly 30 will not release the spearhead 28 while lowering into the hole because the inside diameter of the drill rods 1 limit the travel of the balls 64 to the extent that they bear on the taper between surfaces 42 and 43. This essentially holds the spearhead 28 up so that overshot release coupling 179 may never come into abutting contact with the tubular collar 60 which must occur before disengagement of overshot assembly 30 and inner tube and head assembly can occur. By using such a positive release disengagement of the inner tube 20 and head assembly from the lowering mechanism of the overshot assembly 30 release can be accomplished only when the inner tube 20 is on the bottom of the drill string and the head assembly is locked or latched to the coupling section 2 of the drill string thus insuring controlled release without danger or fear of lost core samples.

Having described a preferred embodiment of this invention in accordance with the patent statutes, it is to be realized that other modifications other than those described may be made Without departing from the broad spirit of this invention. Accordingly, it is respectfully requested that this invention be interpreted as broadly as possible and limited only by the prior art.

What We claim is:

1. A core barrel assembly for use in a drill string comprising, a head assembly axially slidable in such a drill string, latching means for latching connection of said head assembly to such a drill string, core receiving means operatively connected to said head assembly for sliding movement in such drill string and for movement relative to said head assembly, fluid passage means in said head assembly for conducting pressure fluid from an upper portion of such drill string to the lowermost end of such a drill string, a valve located in said passage means operatively connected to said core receiving means and slidably mounted in said head assembly for closing off said fluid passage means upon upward movement of said core receiving means relative to said head assembly, and said valve having an upper fluid reactive surface exposed to said pressure fluid that is equal in area to a lower reactive surface exposed to said pressure fluid on closing off of said fluid passage means.

2 A core barrel assembly for use in a drill string C0111- prising, a head assembly axially slidable in such a drill string, latching means for latching connection of said head assembly to such drill string, core receiving means operatively connected to said head assembly for sliding movement in such a drill string and for movement relative to said head assembly, fluid passage means in said head assembly for conducting pressure fluid from an upper portion of such drill string to the lowermost end of such a drill string, said head assembly including a slidable valve located in said passage means operatively connected to said core receiving means for stopping fluid flow through said fluid passage means upon upward movement of said core receiving means relative to said head assembly and said valve having substantially equal oppositely directed fluid reactive surfaces exposed to said pressure fluid for balancing fluid forces applied to said fluid passage means upon closure of said passage means by said valve.

3. A drill string comprising a plurality of drill rods having a bit attached thereto forming a drill string, means for rotating said drill string, a' tube and head assembly including a core receiver tube axially slidable in said drill string, means for latching said tube and head assembly to said drill string, an overshot assembly having a lower portion operatively connected to said tube and head assembly and comprising means for unlatching said tube and head assembly from said drill string, and said overshot assembly having a pivotal connection thereon for pivoting said lower portion relative to an upper portion of said overshot assembly, said pivotal connection comprising a tubular member with a central bore counter bored to form an annular seat, said tubular member having a first pair of diametrically opposed longitudinally extending slots intersecting said bore intermediate said seat and the end of said tubular member and having closed upper ends, said tubular member having a second pair of diametrically opposed longitudinally extending slots open at the upper ends thereof and extending downwardly a given distance below said closed upper ends, said first and second pairs of slots lie in planes that are normal to each other and intersect along the longitudinal center line of said tubular member, and a shaft having an end engageable with said seat slidably contacting the bore of said tubular member with said shaft having a transversely extending pin with the ends thereof positioned in said first pair of slots respectively said pin being located at a distance from the end of said shaft less than said given dis tance.

References Cited by the Examiner UNITED STATES PATENTS 170,790 12/1875 Way -161 X 511,794 1/1894 Phillips 175-293 1,024,237 4/ 1912 Welker. 2,046,798 7/1936 Thrift 175-246 2,164,598 7/1939 Thrift 175-246 2,209,418 7/1940 Overbeke 251-282 X 2,258,352 10/1941 Catland et a1 175-236 2,347,726 5/ 1944 Auld et a1 175-242 X 2,357,907 9/ 1944 Phillips 175-244 X 2,506,795 5/1950 Koeln 294-861 2,621,959 12/1952 Wiley 294-8617 2,652,232 9/1953 Holland 175-246 2,769,615 11/1956 Burgess 175-246 2,857,138 10/1958 Svendsen et a1. 175-246 X CHARLES E. OCONNELL, Primary Examiner.

BENJAMIN BENDETT, Examiner. 

1. CORE BARREL ASSEMBLY FOR USE IN A DRILL STRING COMPRISING, A HEAD ASSEMBLY AXIALLY SLIDABLE IN SUCH A DRILL STRING, LATCHING MEANS FOR LATCHING CONNECTION OF SAID HEAD ASSEMBLY TO SUCH A DRILL STRING, CORE RECEIVING MEANS OPERATIVELY CONNECTED TO SAID HEAD ASSEMBLY FOR SLIDING MOVEMEMT IN SUCH DRILL STRING AND FOR MOVEMENT RELATIVE TO SAID HEAD ASSEMBLY, FLUID PASSAGE MEANS IN SAID HEAD ASSEMBLY FOR CONDUCTING PRESSURE FLUID FROM AN UPPER PORTION OF SUCH DRILL SRING TO THE LOWEERMOST END OF SUCH A DRILL STRING, A VALVE LOCATED IN SAID PASSAGE MEANS OPERATIVELY CONNECTED TO SAID CORE RECEIVING MEANS AND SLIDABLY MOUNTED IN SAID HEAD ASSEMBLY FOR CLOSING OFF SAID FLUID PASSAGE MEANS UPON UPWARD MOVEMENT OF SAID CORE RECEIVING MEANS RELATIVE TO SAID HEAD ASSEMBLY, AND SAID VALVE HAVING A UPPER FLUID REACTIVE SURFCE EXPOSED TO 